..........can one design around large isolation transformers,
They have 6 leads off the secondary , which is one big coil with one common & 5 others of varying voltage, and one honkin' high amp sec. winding out of #8 wire.

OOPS ! dyslexia strikes again. It ain't a hi-amp secondary---unless you need it for that---- it's the other primary when the battery has to kick in....